Octane on 17' GT

[AlmostFamous]

2 stock 2011-2014 Mustang GT dynos. 91 vs 93 and 87 vs 93.

91 vs 93: Final run it made like 3 rwhp more and 0 rwtq more than the two best 91 octane runs.

87 vs 93: 6 RWHP peak difference. Not that much, but look at the difference in the mid range, especially 4500-6000 rpm. Looks to be ~20 RWHP difference in places (corresponding increase in torque, of course)

5.0 GT Stock dynos 91 octane vs 93 octane

First two runs the car made essentially NO more power.
Then on the third and final run it made like 3 rwhp more and 0 rwtq more than the two best 91 octane runs.

They probably put in the ability to adjust up to 91.5-92 on the high rpm range which gives it a couple extra hp but no additional torque.
I think we can safely say using 93 octane instead of 91 octane gains you 3-4 hp up in the higher rpms for a bit, but as you can see it's not sustained over a large rpm range. So it just may be an anomaly that it made the additional 3 rwhp at the peak.
So 91 octane state people don't need to feel bad, without a tune, guys in 93 octane states aren't getting really any more power out of their stock 5.0's

http://themustangsource.com/forums/f726/5-0-gt-stock-dynos-91-octane-vs-93-octane-487398/

87 vs 93 Octane Dyno Graph

Below is a dyno graph showing the difference between 87 octane and 93 octane. According to the shop, no other changes were made to the car/tune/etc. Similar weather for both passes, car at normal operating temperatures.

Note: 6 RWHP peak difference. Not that much, but look at the difference in the mid range, especially 4500-6000 rpm. Looks to be ~20 RWHP difference in places (corresponding increase in torque, of course).

http://themustangsource.com/forums/f726/87-vs-93-octane-dyno-graph-484635/

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[Wanka]

Thanks everyone. As I've said before, I'm not up to date on the newer stuff and what you've said makes sense. 93 octane is now more readily available, but the price difference to regular for the "old man way" I usually drive probably won't make much difference at all.

Thanks...

 

[ricardocabesa]

Then what's the point of buying a Mustang?

Seriously? Not all of us are Boy Racers/Boulevard Racers.

 

[ricardocabesa]

Thanks everyone. As I've said before, I'm not up to date on the newer stuff and what you've said makes sense. 93 octane is now more readily available, but the price difference to regular for the "old man way" I usually drive probably won't make much difference at all.

Thanks...

I've only put 200 miles on my car but I figured the dealer put regular in the tank prior to delivery (even though I asked for premium) but what I'm doing is adding premium when I reach ~1/2 and afterwards change between regular and premium whenever I reach ~1/2 or thereabouts. But being elderly,the biggest challenge will be remembering what I put in the previous time! Maybe I'll leave the previous receipt in the console.

 

[robwlf]

i run 91 all the time no matter what, and when i do a nice ass grabber weekend blast on a cool weekend i use 93..
when its tuned ill only use 93 as i have with all my tuned cars

 

[csmaan12]

My car feels like a dog below 5K RPMs on 87, and the gas mileage suffered as well.

It equates to a few dollars a fill up difference, so why NOT use 93?

So I'm not going crazy, I too saw a decent difference in MPG when using 87. Specifically about 2mpg, which is noticeable when I normally get 15-17 mpg with the way I drive. Doesn't matter in the end, you don't buy a V8 to save on gas consumption.

 

[jasonstang]

great looks
great handling
435hp
nice interior
was cheaper than porsche 911/bmw m3

Says 435hp but never uses all of it. Might as well have a V6.

 

[jasonstang]

Thanks everyone. As I've said before, I'm not up to date on the newer stuff and what you've said makes sense. 93 octane is now more readily available, but the price difference to regular for the "old man way" I usually drive probably won't make much difference at all.

Thanks...

93 is nice if you own a turbo car. My WRX keeps cut timing on 91. I am gonna try some 93 next time.
A lot of new turbo direct injection engine will benefit from 93.

 

[RaceRed5.0]

Everyone pretty much answered it, It really comes down to do you care for a slight HP gain or are you more concerned about MPG and using it as a everyday driver? If you chose the latter than probably a V8 is the wrong car for you. Or you can always get a cheap used daily driver civic or corolla put liability on it and save your Stang for the weekends for Friday drives.

 

[jasonstang]

Seriously? Not all of us are Boy Racers/Boulevard Racers.

Then why have all that power.
[ame]
[ame]

 

[MX5Racer]

Then why have all that power.

Get over yourself, dude

 

[Rocketman]

Says 435hp but never uses all of it. Might as well have a V6.

So because he would lose a handful of HP with a lower octane, he might as well go to a lower spec engine and lose over 100 hp? Logic not even once.

 

[jasonstang]

So because he would lose a handful of HP with a lower octane, he might as well go to a lower spec engine and lose over 100 hp? Logic not even once.

If he is only using 100hp driving around might as well save money on a 300hp V6.

 

[jeffdeq]

I’ve had my 2017 GT convertible for 8 months now and approaching 5000 miles. I use 87 octane non-ethanol fuel from Murphy USA. I get 22+ mpg in town and 26+ mpg on the highway. There has been no performance issues but I do not drive the car hard. More easy cruising than anything else. I stick with non-ethanol because it provides a more smooth idle at red lights.

My 2 cents!

 

[jeffdeq]

Everyone pretty much answered it, It really comes down to do you care for a slight HP gain or are you more concerned about MPG and using it as a everyday driver? If you chose the latter than probably a V8 is the wrong car for you. Or you can always get a cheap used daily driver civic or corolla put liability on it and save your Stang for the weekends for Friday drives.

Weekend and Friday drives for me too but I have that burst of power when I want it!

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